With the introduction of interactive computer graphics in the 1960s, the field of cartography made significant advances in both quality and productivity. Digital-type methods began to be used for gathering map data, and processing it to more accurately model terrain and geographic features. For example, systems and methods could be used to digitize data representing terrain and geographic features, and then the terrain and features could be stored as a “digital source map.” The digital source map could then be output to a mechanical printing device, such as a color printer. However, the information stored in a digital source map was limited since the annotation and manipulation of digitized data for map finishing was limited until the advent of graphical editing programs such as Intergraph's IGDS in 1972, Autodesk's AutoCAD in 1982 and Adobe Systems' Photoshop in 1985. These types of products allowed users to use computer systems to produce paper maps that were of comparable quality to hand drawn maps.
A further improvement in the use of computers in mapping was the development of Graphical Information Systems, or GIS, based on work at The Harvard Lab for Computer Graphics in the mid 1970's. The first commercial GIS was ESRI's ARC/INFO, released in 1982. GIS allowed the inclusion into digital source maps of significant amounts of non-graphic information about terrain and geographical features as well as positional information based on accurate cartographical methods beyond those of earlier CAD based systems. The non-graphic information and positional information could be stored in a digital map as “objects.” In GIS, objects were said to be geo-registered, since the objects were associated with a specific position in the digital source map. Thus GIS users could obtain much more information about the terrain and geographical features associated with respective objects displayed in these types of digital source maps than with terrain and features represented in earlier systems and methods of mapping.
The end product of both early CAD-based and GIS-based mapping systems were paper maps, which obviously could not display information other than that printed on the page. While the originals of these maps existed in computer files as digital source maps, which could be used to display objects associated with non-graphic information about terrain and geographical features shown on the paper maps, access to the digital source maps was limited to users with the appropriate proprietary software who were physically connected to a network containing the digital source map data. Although these digital map files could be copied to floppy disks or tapes for transferring to other users, these conventional systems and methods were too cumbersome for widespread and high-speed distribution. The emergence of high-speed networks, the Internet and the CD-ROM device in the 1990's extended user access to digital source map data outside the physical connectivity of the originator's network, but still required user access to a software package related to that of the original producer. Those users having such access were able to derive substantial additional value from digital source map data. For example, a user of Intergraph's Fieldview product could see both the position of a piece of equipment on a digital source map and display many attributes of the equipment, such as manufacturer, part number, installation date, voltage, phase, and status. However, this product required that the user acquire a specific and expensive software program along with a specific and expensive high performance computer and computer operating system. Its utility was further restricted by the need to distribute a complete and complex proprietary data set, rather than individual, cartographically complete map files.
In 1987, Adobe Systems introduced the portable document format (PDF) file structure and the associated viewer application program Adobe Acrobat®. These products allowed the conversion of almost any Microsoft Windows® compliant file structure to a single structure which retained the complete and faithful appearance of all the originals, regardless of their source. Aided by the availability of a free and robust viewing product, Acrobat Reader®, and the publication of the file format specification as an open standard, the PDF file format quickly became a defacto standard for electronic document publishing.
The PDF file format for drawing distribution provides a faithful, inviolable rendering, distributed electronically at very low cost, with significant work flow and security features. The PDF file format provides other features beyond these capabilities, some which may not be available in other distribution methods and systems, regardless of file format. Since the PDF file format is both an open format and a very rich structure that offers many ways to extend its functionality beyond mere viewing, there are functionalities that may exceed those available from the original source file.
For example, software can be used to convert native CAD files to PDF files. The software may be designed to enhance the basic PDF file format by including structures enabled by the PDF file specification which increase the utility of PDF files to engineering and mapping users. While the PDF file format allows for the distribution of digital source maps electronically without the need for appropriate viewing software, hardware or operating system, it has been limited to the graphics or digitized map images only. Users of maps frequently have a need to determine the position of an object in one of many different geographical coordinate systems. For example, a military user may desire to communicate the position of a target located on a map by determining its latitude and longitude in the World Geodetic System. With paper maps, this can be done through a manual method of measuring the scaled offset of a point from a known landmark, then adding that value to the documented coordinates of the landmark. Since prior digital source maps in the PDF file format or other file format are merely graphical images of the digital source map, and the electronic maps in PDF file format did not allow for the inclusion of geo-registered data or provide an accurate determination of the position of objects shown on the digital source map, there was no way of automatically determining the coordinates of an arbitrarily selected point in an arbitrarily selected coordinate system.
The PDF file format allows the embedding of annotations and hyperlinks within the file. Annotations can contain annotation information such as any sequence of text and numbers, while the hyperlinks can perform any number of functions common to computer systems. For example, a hyperlink can move the viewing position to another part of the image, open another image for display, or invoke another computer program. The content of annotation information associated with an annotation can include information about an object depicted in the map, and this information may exist in an external database along with the coordinates of the location of the item in one of many coordinate systems. For example, a database entry can include the manufacturer, part number, installation date, voltage, phase, and status of a piece of equipment. However, no prior systems or methods existed for embedding these annotations and hyperlinks in the PDF file format using their geographic coordinates.
Another useful functionality of the PDF file format is the ability to render text strings from a native file as text strings within a corresponding PDF file, thus preserving the native font characteristics. Thus, all text within the PDF file may become fully searchable. This allows for a set of PDF files to be cataloged, enabling full text searching over a very large set of drawings, using the cataloging function. This text searchability can even be extended to internet or intranet web searching, so that documents exposed to the Internet or World Wide Web (WWW) can be located using web search engines like Google™. However, the text searchability for digital source maps stored in a PDF file format has not been fully utilized by conventional mapping systems and methods.
These and other drawbacks of systems and methods utilizing a graphics file format such as the PDF file format are illustrated by at least one prior patent, U.S. Pat. No. 6,336,074 to Woo. Woo relates to a database of maps stored in a portable document format (PDF) file. The PDF file can be accessible using a mobile navigation system with a global positioning system (GPS) receiver. Each PDF file can be independent of any hardware, software and operating system used to create it. However, Woo does not appear to allow for the inclusion of geo-registered data or provide an accurate determination of the position of objects shown on a digital source map.
Furthermore, Woo relates to providing descriptions of documents including any combination of text, graphics, and images in a device-independent and resolution-independent format. In accordance with Woo, a PDF file can contain graphics and hypertext links or information. Hypertext accesses of data can be communicated from the GPS receiver to a map and hypertext database. When a hypertext link or information is called upon, the map and hypertext database can return a point-of-interest name and a map coordinate location. While Woo's method does extend the ability of a user to obtain information regarding points of interest on a map, it accomplishes this in such a way as to place major restrictions on the user. The method described can allow for the construction of a graphic representing a local area map that includes a set of points-of-interest; composing special text and details related to said points-of-interest in a hypertext file; and encapsulating said map graphics and hypertext information in a portable document format (PDF) file. However, the method does not allow the user to determine coordinates of arbitrarily selected points on the map, nor does it allow for the transformation of points from one coordinate system to another. Furthermore, the method of relating the hypertext to the points-of-interest is not related to their geographic coordinates in an arbitrarily selected coordinate system. Finally, Woo's method requires that the user have access to a mobile navigation system that includes a GPS navigation receiver.
Therefore a need exists for methods and systems for encoding and rendering geographic coordinates and features in a graphics-type file format such as a portable document format (PDF) file enabling the creation of a self-contained, general purpose cartographical document which is independent of a particular hardware platform or computer operating system for its use.
Another need exists for methods and systems for annotating geographic coordinates and features in a graphics-type file format such as a portable document format (PDF) file.
Yet another need exists for methods and systems for cross-referencing a database using an annotation embedded in a graphics-type file format such as a portable document format (PDF) file.